What NASA’s Next Mars Rover Will Discover

NASA’s Mars Science Laboratory is on its way. In a little more than a month, the 1-ton rover, which launched in November, will descend to the Martian surface.

The nuclear-powered robot is designed to make spectacular new discoveries about the Red Planet. It will drill and analyze the Martian soil to search for signs of water, past or present, and determine whether or not the planet was ever able to support life.

MSL dwarfs its immediate predecessors, the rovers Spirit and Opportunity and could almost crush the first Martian rover, Sojourner, beneath one wheel. Bringing a robot this large down safely necessitates a never-before-attempted landing system, though the increased size has let scientists pack 10 state-of-the-art instruments aboard and should allow the robot to rove farther than any before.

“Every time we land a new rover on Mars, our ability to understand the surface increases tremendously,” said geologist John Grotzinger of Caltech who is the project scientist for the mission.

While scientists don’t know exactly what new findings await the rover, they have good ideas of what they want to look for. The first few weeks of MSL’s life on Mars are already planned out in detail and after the mission starts in earnest, researchers have a number of targets they are eager to explore.

Here, Wired takes a look at MSL’s game plan after it gets its wheels on the ground on Aug. 5, and the early discoveries scientists are hoping to make.

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Nail-Biting Landing

MSL’s sky crane represents a brand new way to get a rover down to the surface of Mars. When the lander approaches the ground, it will fire rockets and hover 25 feet over the surface and then gently lower the robot down on wires. This landing system represents the limits of current technology, making MSL the largest mass to ever touch down on the Red Planet.

The new method doesn’t ruffle the science team too much.

“We’re actually really excited about the fact that we’ve got this guided entry capability,” said Grotzinger, adding that it allowed researchers to pinpoint their landing site with greater precision than ever. “People get nervous about sky crane, but it’s really a better landing system from a safety point of view.”

Stretching Out

Like a newborn flexing its fingers, MSL will need to test out its various instruments after reaching the surface. The rover’s first six days are already planned out in exacting detail.

The scripted regimen will make sure everything is in working order and returning early sample data to scientists on Earth. Previous rovers were ready to roll after only a day or two of logistics but MSL will need nearly a week to complete this testing phase.

During the robot’s first day on Mars, it will calibrate instruments and return its first color image, said John Grotzinger, project scientist for the mission.

“The camera is aimed outward, so we should get a pretty nice-looking view of the landscape in whatever direction we’re pointed,” he said.

On the second day the rover will use its various gadgets to look at the surrounding soil composition and take a full 360-degree camera shot of the area. During this initial check, MSL will scope out nearby areas of interest. The science team may decide to move to a new area, do some scooping and drilling, take samples, and analyze them.

There is a good chance that the rover will land next to layered sedimentary bedrock, a potentially exciting circumstance. On Earth, these rocks are often a storehouse for ancient biological materials and organic carbon. If anything equivalent exists on Mars, it might turn up.

After the first few weeks, the rover will complete its early test phase. “We’ll have used every instrument and device on the rover,” said Grotzinger. “Then we get the keys and begin the science in earnest.”

Image: MSL can fire a targeted laser to vaporize a small bit of Martian soil or rock and analyze the resulting smoke. NASA/JPL-Caltech

Check for Methane

For the last decade or so, scientists have detected something strange wafting around the atmosphere of Mars: methane. This simple compound is notable because it tends not to stick around for along time and needs to be continuously replenished. Though volcanoes produce it, here on Earth one major source of methane is living organisms. Could the gas similarly indicate life on Mars?

As yet, the findings remain controversial. Some scientists say they have absolutely detected methane while other researchers have failed to find any. MSL will hopefully provide a definitive confirmation or denial.

Within the first 10 days after landing, the rover will be rotated to point upwind, and then it will literally sniff the air. An instrument specifically designed to analyze organics and gases from the atmosphere will try to detect methane.

“If there is methane in the atmosphere of Mars, it would be a major discovery,” said John Grotzinger, project scientist for the mission. The finding would bolster that case for living creatures on present-day Mars.

Even if MSL finds nothing on its initial sniff, it doesn’t doom the methane prospects. The methane could appear intermittently, perhaps triggered by changes in the seasons. The rover will continue scoping out methane gas for at least a Martian year. If it still fails to find anything, scientists will have to go back to the drawing board and try to understand why they ever thought there should be methane in the first place.

Rocky Landing

MSL will land inside of Gale crater, an ancient impact site between 3.5 and 4 billion years old. The area has been extensively mapped from satellites in orbit but the rocks in this area show a curious combination of properties: They are simultaneously very bright yet trap heat easily.

Rocks that hold onto heat very well are typically dark in color, like lava flows. Bright rocks tend to be porous and full of air holes that don’t retain heat. Figuring out the exact composition of the bedrock that MSL lands on will be the mission’s first major challenge.

“Right off the bat, we’re landing on something that we’re very curious about,” said John Grotzinger, project scientist for the mission.

Scientists think that, billions of years ago, Gale crater was filled with water, which would have made the rocks at MSL’s landing site porous and bright. One possibility is that water flowed through this rock at a later date, depositing minerals, making it denser and better able to retain heat. MSL’s investigations will hopefully help figure out the complex aqueous history of the area.

Young Craters

After MSL gets its bearings and starts driving, it will head to the bottom of Mt. Sharp, a large hill at the center of Gale crater.

On its way to the mountain’s base, the rover will likely pass small craters created within the last 100,000 years. The science team hopes to use these impacts – which will likely have blown out chunks of interesting bedrock — to investigate the area in detail.

Though the robot is equipped with a drill, the small punctures will provide an unparalleled window into the upper layers of the Martian bedrock. Determining the composition of these layers could turn up interesting minerals that will help tease out the history of the area.

Phyllosilicate Landscape

Six to nine months after landing, MSL should arrive at the base of Mt. Sharp and begin climbing. This 3-mile-high massif in the center of Gale crater is much more like a shield volcano on Hawaii than K2. The slope is shallow enough that the rover will be able to simply drive up the mountain

Near the bottom, MSL should encounter phyllosilicates, a type of clay mineral, which often form in the presence of lots of water. Investigations of these minerals could provide details about the water that once flowed in this region, such as how acidic it was. If the water was fairly neutral, it could be a good indication for the possibility of ancient Martian life.

The clays are likely also good at sequestering organic chemistry, if it ever existed. MSL will scoop up soil samples and analyze them for organic carbon. Not finding carbon, though, wouldn’t rule out the possibility that there was ever life.

Even on Earth, a place we know has been teeming with life for billions of years, organic carbon does not always preserve well. The problem is that water circulating through rocks tends to break down any evidence of life.

“On Earth we’ve learned an important lesson: Where you get water you can get life but where you get water you can also destroy any chemical evidence of it,” said John Grotzinger, project scientist for the mission.

Strange Fractures

Once MSL begins climbing Mt. Sharp, it will come to a number of strange locations.

Coming over one ridge, it will suddenly encounter an enormous fracture network. These features formed when geological processes broke the ground into large rectangular shapes, generating deep crevices. Over million of years, the areas were filled with minerals.

The features are of interest because the deep crevices may have once provided a potentially habitable underground environment. MSL will drill down into the mineral deposits within the fracture network and sample them, perhaps turning up evidence of past life or good habitable conditions.

The MSL team hopes to reach this spot within two years of landing on Mars.

What's Next?

Once MSL reaches the two-year point, it will have completed its scheduled science mission.

“After that the warranty expires and we’re officially living on borrowed time,” said John Grotzinger, project scientist for the mission.

But the rover will have only made it a half-mile up Mt. Sharp in that time. The team hopes the rover will still have enough juice – and NASA funding – to continue on with their explorations.

Past rovers provide a good indication of robustness. The Spirit and Opportunity robots were initially scheduled for a three-month mission. Spirit made it for six years before shutting down while Opportunity is still roving around the surface nearly eight years after landing.

In all likelihood, the mission designers will choose to continue sending MSL up the mountain. Scientists are eager to explore the transition point where evidence for liquid water in Mars’ history ends. Searching this area could give them insight into how and why Mars went from being a wet world to the arid planet it is today – the details of which remain unresolved.

While MSL is billed as a mission searching for habitable areas, even finding no evidence for organics will be beneficial to scientists, said Grotzinger.

The evolution of life on Earth was dependent on its environment. If organisms never evolved on Mars, being able to contrast and compare the two environments could provide great insight into our own biosphere.

Grotzinger brings up the famous thought experiment suggested by evolutionary biologist Stephen Jay Gould: If you could rewind the tape of life on Earth and run it again, how much would be inevitable and how much would depend on historical accident?

Going to Mars is like replaying the tape, he said. “We can see the early evolution of a terrestrial planet that’s really Earth-like.”

Image: The proposed pathway that MSL will take during its first two years on the Martian surface. NASA/JPL-Caltech/ASU/UA